Conventional surge arresters protect underground and overhead electrical systems from transient over-voltage surges from lightning, switching, and the like. Traditionally, a 200 Ampere (200 A) elbow arrester configuration is used to address the surges. In this configuration, the bushing of the desired apparatus designed to protect against the surges is connected to a first portion of the elbow connection. An arrester, typically consisting of metal oxide varistor (MOV) elements, is positioned in the second portion of the elbow connector. The MOV elements and bushing are electrically connected in an intermediate portion of the first part of the elbow connection. A ground connector—which is positioned at an end of the second portion of the elbow connector—is electrically connected to the MOV on a first end and coupled to an external ground on a second end. Therefore, a voltage is applied across the MOV elements from the bushing connection of the apparatus and ground. At steady state, the MOV elements have a relatively high impedance, however as the voltage applied across the elements increases, such as from a lightning surge, the impedance of the MOV elements decreases until a breakdown voltage, wherein the impedance rapidly decreases towards zero. As a result, the MOV elements become highly conductive and serve to conduct transient current from the surge voltage to ground, thereby protecting the apparatus. Such elbow arrester configurations include a pulling eye, which enables a lineman to install and remove the arrester utilizing a fiberglass hot stick attached to the pulling eye.
In applications of loads higher than 200 A, a bolted-style connector system requires an adapter known as a load break reducing tap plug (LRTP), which, in conjunction with an extender is coupled to the first portion of the 200 A elbow arrester. Exemplary bolted-style connector systems include but are not limited to 400 A, 600 A, and 700 A. The inherent disadvantage of using such a system is that the additional parts introduce a higher impedance, installation complexities, and fault points for the system. In addition, the increased overall stack height of the system can make it difficult to install in underground systems where space allocation is limited.
Such inherent disadvantages in known systems have not been entirely ignored in the industry. One method of eliminating the load break reducing tap plug incorporates the arrester block directly into an apparatus capable of mating with, and latching to, a standard bolted-style bushing connector. This method typically requires a connector that is bolted and torqued to the bushing. A disadvantage of this method is that assembly and removal of the bolted connector can be difficult and require additional tools.
Therefore, a need exists in the field for an arrester with a push on method of coupling to a cable accessory.